Many computing devices are equipped with hardware that allows the computing device to wirelessly connect to a network or to other computing devices. Such wireless hardware frequently contains one or more radios, each with a transmitter, a receiver and data processing components.
In some devices, the wireless hardware has a predefined configuration such that each radio supports a connection according to a specific wireless technology, such as Wi-Fi, WiMAX, Bluetooth or HSDPA. For example, such a radio may communicate using a predefined frequency or frequencies and use a predefined sequence of control messages to connect with another device or exchange information. To support communication with different devices communicating using different wireless technologies, the wireless hardware may include multiple radios, each configured for communication using a specific wireless technology. Each radio may be coupled to its own antenna, frequently implemented as a patch antenna on a surface of a printed circuit board on which the radio is implemented or embedded within the shell of the computer. Though some radios may support a number of closely related wireless technologies, such as variations of the 802.11 Standard, a radio with a predefined configuration is generally limited in the wireless technologies it can support.
In other devices, the wireless hardware may be configurable such that the wireless technology used for communication may change under software control, implementing what is sometimes called a “software defined radio.” The wireless hardware is adapted to receive control inputs that can change operating parameters of the radio, such as the frequencies used for communication or data processing performed on received signals. By reconfiguring the operating parameters of the hardware, it may be possible for one group of hardware components to act as a radio for different wireless technologies.